1. Field of the Invention
The present invention relates to a light shielding structure of a lens barrel including an inner ring and an outer ring, at least one of which rotates relative to the other, and the inner ring has at least one through cutout portion which radially extends through the inner ring to allow the entry of harmful light.
2. Description of the Related Art
Lens barrels used for optical devices such as cameras are often provided with an inner ring and an outer ring, at least one of which being rotatable relative to the other. In such conventional lens barrels, it is often the case that a light shielding structure such as a labyrinth structure is formed on the inner ring and the outer ring therebetween in the vicinity of their respective front ends. However, if such a labyrinth structure is formed between the inner ring and the outer ring, at least one of which being rotatable relative to the other, it is necessary to provide a large clearance between the inner ring and the outer ring in order to accommodate eccentricity of the inner ring or the outer ring relative to the other. This increases the diameter of the lens barrel or the resistance to relative rotation between the inner ring and the outer ring.